The proposed research is designed to study the natural history and pathogenesis of primary retinitis pigmentosa (RP), employing psychophysical measures of visual function, retinal densitometry, angiography, and collaborative biochemical studies. In the various forms of RP our broad objectives are to: 1) determine the nature of the onset, 2) characterize the relation of rod dysfunction to cone dysfunction, 3) characterize the nature of disease progression, and 4) better define and characterize the emerging RP categories. In addition to these broad objectives, we are proposing to determine: 1) the mechanisms for absolute threshold elevations, 2) the origin of color discrimination loss, 3) the role fo vitreous degeneration, and 4) the reason for high myopia in the various forms of RP.